git.meshlink.io Git - meshlink/blob - src/uml_device.c

   1 /*
   2     device.c -- UML network socket
   3     Copyright (C) 2002-2005 Ivo Timmermans,
   4                   2002-2012 Guus Sliepen <guus@tinc-vpn.org>
   5
   6     This program is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     This program is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License along
  17     with this program; if not, write to the Free Software Foundation, Inc.,
  18     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19 */
  20
  21 #include "system.h"
  22
  23 #include <sys/un.h>
  24
  25 #include "conf.h"
  26 #include "device.h"
  27 #include "net.h"
  28 #include "logger.h"
  29 #include "utils.h"
  30 #include "route.h"
  31 #include "xalloc.h"
  32
  33 static int listen_fd = -1;
  34 static int request_fd = -1;
  35 static int data_fd = -1;
  36 static int write_fd = -1;
  37 static int state = 0;
  38 static char *device_info;
  39
  40 extern char *identname;
  41 extern volatile bool running;
  42
  43 static uint64_t device_total_in = 0;
  44 static uint64_t device_total_out = 0;
  45
  46 enum request_type { REQ_NEW_CONTROL };
  47
  48 static struct request {
  49   uint32_t magic;
  50   uint32_t version;
  51   enum request_type type;
  52   struct sockaddr_un sock;
  53 } request;
  54
  55 static struct sockaddr_un data_sun;
  56
  57 static bool setup_device(void) {
  58         struct sockaddr_un listen_sun;
  59         static const int one = 1;
  60         struct {
  61                 char zero;
  62                 int pid;
  63                 int usecs;
  64         } name;
  65         struct timeval tv;
  66
  67         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  68                 xasprintf(&device, LOCALSTATEDIR "/run/%s.umlsocket", identname);
  69
  70         get_config_string(lookup_config(config_tree, "Interface"), &iface);
  71
  72         device_info = "UML network socket";
  73
  74         if((write_fd = socket(PF_UNIX, SOCK_DGRAM, 0)) < 0) {
  75                 logger(LOG_ERR, "Could not open write %s: %s", device_info, strerror(errno));
  76                 running = false;
  77                 return false;
  78         }
  79
  80 #ifdef FD_CLOEXEC
  81         fcntl(write_fd, F_SETFD, FD_CLOEXEC);
  82 #endif
  83
  84         setsockopt(write_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof one);
  85
  86         if(fcntl(write_fd, F_SETFL, O_NONBLOCK) < 0) {
  87                 logger(LOG_ERR, "System call `%s' failed: %s", "fcntl", strerror(errno));
  88                 running = false;
  89                 return false;
  90         }
  91
  92         if((data_fd = socket(PF_UNIX, SOCK_DGRAM, 0)) < 0) {
  93                 logger(LOG_ERR, "Could not open data %s: %s", device_info, strerror(errno));
  94                 running = false;
  95                 return false;
  96         }
  97
  98 #ifdef FD_CLOEXEC
  99         fcntl(data_fd, F_SETFD, FD_CLOEXEC);
 100 #endif
 101
 102         setsockopt(data_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof one);
 103
 104         if(fcntl(data_fd, F_SETFL, O_NONBLOCK) < 0) {
 105                 logger(LOG_ERR, "System call `%s' failed: %s", "fcntl", strerror(errno));
 106                 running = false;
 107                 return false;
 108         }
 109
 110         name.zero = 0;
 111         name.pid = getpid();
 112         gettimeofday(&tv, NULL);
 113         name.usecs = tv.tv_usec;
 114         data_sun.sun_family = AF_UNIX;
 115         memcpy(&data_sun.sun_path, &name, sizeof name);
 116
 117         if(bind(data_fd, (struct sockaddr *)&data_sun, sizeof data_sun) < 0) {
 118                 logger(LOG_ERR, "Could not bind data %s: %s", device_info, strerror(errno));
 119                 running = false;
 120                 return false;
 121         }
 122
 123         if((listen_fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 124                 logger(LOG_ERR, "Could not open %s: %s", device_info,
 125                            strerror(errno));
 126                 return false;
 127         }
 128
 129 #ifdef FD_CLOEXEC
 130         fcntl(device_fd, F_SETFD, FD_CLOEXEC);
 131 #endif
 132
 133         setsockopt(listen_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof one);
 134
 135         if(fcntl(listen_fd, F_SETFL, O_NONBLOCK) < 0) {
 136                 logger(LOG_ERR, "System call `%s' failed: %s", "fcntl", strerror(errno));
 137                 return false;
 138         }
 139
 140         listen_sun.sun_family = AF_UNIX;
 141         strncpy(listen_sun.sun_path, device, sizeof listen_sun.sun_path);
 142         if(bind(listen_fd, (struct sockaddr *)&listen_sun, sizeof listen_sun) < 0) {
 143                 logger(LOG_ERR, "Could not bind %s to %s: %s", device_info, device, strerror(errno));
 144                 return false;
 145         }
 146
 147         if(listen(listen_fd, 1) < 0) {
 148                 logger(LOG_ERR, "Could not listen on %s %s: %s", device_info, device, strerror(errno));
 149                 return false;
 150         }
 151
 152         device_fd = listen_fd;
 153         state = 0;
 154
 155         logger(LOG_INFO, "%s is a %s", device, device_info);
 156
 157         if(routing_mode == RMODE_ROUTER)
 158                 overwrite_mac = true;
 159
 160         return true;
 161 }
 162
 163 void close_device(void) {
 164         if(listen_fd >= 0)
 165                 close(listen_fd);
 166
 167         if(request_fd >= 0)
 168                 close(request_fd);
 169
 170         if(data_fd >= 0)
 171                 close(data_fd);
 172
 173         if(write_fd >= 0)
 174                 close(write_fd);
 175
 176         unlink(device);
 177
 178         free(device);
 179         if(iface) free(iface);
 180 }
 181
 182 static bool read_packet(vpn_packet_t *packet) {
 183         int lenin;
 184
 185         switch(state) {
 186                 case 0: {
 187                         struct sockaddr sa;
 188                         socklen_t salen = sizeof sa;
 189
 190                         request_fd = accept(listen_fd, &sa, &salen);
 191                         if(request_fd < 0) {
 192                                 logger(LOG_ERR, "Could not accept connection to %s %s: %s", device_info, device, strerror(errno));
 193                                 return false;
 194                         }
 195
 196 #ifdef FD_CLOEXEC
 197                         fcntl(request_fd, F_SETFD, FD_CLOEXEC);
 198 #endif
 199
 200                         if(fcntl(listen_fd, F_SETFL, O_NONBLOCK) < 0) {
 201                                 logger(LOG_ERR, "System call `%s' failed: %s", "fcntl", strerror(errno));
 202                                 running = false;
 203                                 return false;
 204                         }
 205
 206                         close(listen_fd);
 207                         listen_fd = -1;
 208                         device_fd = request_fd;
 209                         state = 1;
 210
 211                         return false;
 212                 }
 213
 214                 case 1: {
 215                         if((lenin = read(request_fd, &request, sizeof request)) != sizeof request) {
 216                                 logger(LOG_ERR, "Error while reading request from %s %s: %s", device_info,
 217                                            device, strerror(errno));
 218                                 running = false;
 219                                 return false;
 220                         }
 221
 222                         if(request.magic != 0xfeedface || request.version != 3 || request.type != REQ_NEW_CONTROL) {
 223                                 logger(LOG_ERR, "Unknown magic %x, version %d, request type %d from %s %s",
 224                                                 request.magic, request.version, request.type, device_info, device);
 225                                 running = false;
 226                                 return false;
 227                         }
 228
 229                         if(connect(write_fd, &request.sock, sizeof request.sock) < 0) {
 230                                 logger(LOG_ERR, "Could not bind write %s: %s", device_info, strerror(errno));
 231                                 running = false;
 232                                 return false;
 233                         }
 234
 235                         write(request_fd, &data_sun, sizeof data_sun);
 236                         device_fd = data_fd;
 237
 238                         logger(LOG_INFO, "Connection with UML established");
 239
 240                         state = 2;
 241                         return false;
 242                 }
 243
 244                 case 2: {
 245                         if((lenin = read(data_fd, packet->data, MTU)) <= 0) {
 246                                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
 247                                            device, strerror(errno));
 248                                 running = false;
 249                                 return false;
 250                         }
 251
 252                         packet->len = lenin;
 253
 254                         device_total_in += packet->len;
 255
 256                         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
 257                                            device_info);
 258
 259                         return true;
 260                 }
 261
 262                 default:
 263                         logger(LOG_ERR, "Invalid value for state variable in " __FILE__);
 264                         abort();
 265         }
 266 }
 267
 268 static bool write_packet(vpn_packet_t *packet) {
 269         if(state != 2) {
 270                 ifdebug(TRAFFIC) logger(LOG_DEBUG, "Dropping packet of %d bytes to %s: not connected to UML yet",
 271                                 packet->len, device_info);
 272                 return false;
 273         }
 274
 275         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 276                            packet->len, device_info);
 277
 278         if(write(write_fd, packet->data, packet->len) < 0) {
 279                 if(errno != EINTR && errno != EAGAIN) {
 280                         logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device, strerror(errno));
 281                         running = false;
 282                 }
 283
 284                 return false;
 285         }
 286
 287         device_total_out += packet->len;
 288
 289         return true;
 290 }
 291
 292 static void dump_device_stats(void) {
 293         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 294         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
 295         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
 296 }
 297
 298 const devops_t uml_devops = {
 299         .setup = setup_device,
 300         .close = close_device,
 301         .read = read_packet,
 302         .write = write_packet,
 303         .dump_stats = dump_device_stats,
 304 };